STUDY DESIGN: Retrospective review of prospectively collected data. PURPOSE: To evaluate the incidence of surgical site infections (SSIs) in minimally invasive spine surgery (MISS) in a cohort of patients and compare with available historical data on SSI in open spinal surgery cohorts, and to evaluate additional direct costs incurred due to SSI. OVERVIEW OF LITERATURE: SSI can lead to prolonged antibiotic therapy, extended hospitalization, repeated operations, and implant removal. Small incisions and minimal dissection intrinsic to MISS may minimize the risk of postoperative infections. However, there is a dearth of literature on infections after MISS and their additional direct financial implications. METHODS: All patients from January 2007 to January 2015 undergoing posterior spinal surgery with tubular retractor system and microscope in our institution were included. The procedures performed included tubular discectomies, tubular decompressions for spinal stenosis and minimal invasive transforaminal lumbar interbody fusion (TLIF). The incidence of postoperative SSI was calculated and compared to the range of cited SSI rates from published studies. Direct costs were calculated from medical billing for index cases and for patients with SSI. RESULTS: A total of 1,043 patients underwent 763 noninstrumented surgeries (discectomies, decompressions) and 280 instrumented (TLIF) procedures. The mean age was 52.2 years with male:female ratio of 1.08:1. Three infections were encountered with fusion surgeries (mean detection time, 7 days). All three required wound wash and debridement with one patient requiring unilateral implant removal. Additional direct cost due to infection was $2,678 per 100 MISS-TLIF. SSI increased hospital expenditure per patient 1.5-fold after instrumented MISS. CONCLUSIONS: Overall infection rate after MISS was 0.29%, with SSI rate of 0% in non-instrumented MISS and 1.07% with instrumented MISS. MISS can markedly reduce the SSI rate and can be an effective tool to minimize hospital costs.
Cohort Studies ; Debridement ; Decompression ; Diskectomy ; Health Expenditures ; Hospital Costs ; Hospitalization ; Humans ; Incidence ; Minimally Invasive Surgical Procedures ; Prospective Studies ; Retrospective Studies ; Spinal Stenosis ; Spine* ; Surgical Wound Infection* ; Wounds and Injuries

STUDY DESIGN: Cross-sectional study. PURPOSE: To accurately measure the dimensions of cervical endplates based on computed tomography (CT) scans in Indian population and assess accuracy of match with currently available cervical disc prostheses. OVERVIEW OF LITERATURE: The dimensions of currently available cervical disc replacement implants are based on early published geometrical measurements of vertebrae endplates for Caucasian population. To author's knowledge, similar study has not been published for patients from Indian subcontinent. METHODS: CT scans of cervical spine of patients from Indian subcontinent were collected and reviewed. Seventy patients (54 men and 16 women; aged 18-56 years with average of 37 years) who underwent CT scans of cervical spine were included in study. 3D CT scans of sub axial cervical spine (C3 to C7) were analyzed. The anterior-posterior (AP) and central mediolateral (CML) dimensions of superior and inferior endplates from C3 to C7 were measured using digital measuring system. RESULTS: A total of 560 endplates of 70 patients were included in the study. The AP diameter of cervical endplates ranged from 0.87 to 2.47 cm. The CML diameters ranged from 0.84 to 2.98 cm. For levels C3/C4 and C4/C5 for AP dimension Prestige-LP (90.5%) and Prodisc-C (89%) discs showed higher percentage of matching than Discover discs (58.5%). For CML diameter, Prestige-LP (69.5%), Prodisc-C (70%) and Discover (39.5%) discs showed almost similar matching with measured endplates. For levels C5/C6 and C6/C7 for AP dimension, Prestige-LP (67.25%), Prodisc-C (49.35%) and Discover (51.5%) discs showed similar matching. For CML diameter Prestige-LP (32%), Prodisc-C (27.5%) and Discover (42.2%) discs showed poor matching with measured endplates. CONCLUSIONS: This study indicates need for redesign of cervical disc prostheses to match Indian patients. The collected anthropometric dimensions from this study may be used to design and develop indigenous artificial total disc replacement prosthesis and even cervical cages in India. With the present study being a small pilot study, the authors recommend anthropometric CT measurements in larger number of Indian patients in order to validate footprint dimensions for designing better-matched prosthesis.
Anthropometry* ; Cross-Sectional Studies ; Female ; Humans ; India ; Male ; Pilot Projects ; Prostheses and Implants ; Spine ; Tomography, X-Ray Computed ; Total Disc Replacement*

Methods: This retrospective pilot study was performed at single center on 858 spine surgery patients. The patients were divided into the following two groups: the study group (after implementation of the checklist [2016–2017]) and the control group (before the implementation of the checklist [2015–2016]). The incidence of common preventable human errors and major perioperative complications in spine surgeries were recorded and compared between the two groups. Results: The prevalence of wrong-level surgeries was 0%, and the overall prevalence of the preventable errors was 1.63% (7/428). The rate of adverse, near-miss, and no-harm events was 0.23% (1/428), 0.70% (3/428) and 0.70% (3/428), respectively. The preoperative, intraoperative, and postoperative errors were 0.70% (3/428), 0.23% (1/428), and 0.70 (3/428), respectively. The reoperation rate related to preventable errors reduced after the checklist was used. There were significant differences in the total preventable errors related to complications, such as infections, prolonged hospital stays, and unplanned hospital readmission/revision surgeries (p=0.001) Conclusions The authors propose the first-of-its kind spine surgery-specific checklist that is comprehensive and involves perioperative parameters. The checklist is easy to use, safe, and effective for reducing the unforgiving errors and perioperative complications. However, its broader implementation would require validation in large, multi-center, randomized control studies.

Methods: Four FE models of multilevel posterior cervical fixation were created and tested by FEA in various permutations and combinations. Generic differences in fixation were determined, and the following parameters were assessed: (1) maximum moment at failure, (2) maximum angulation at failure, (3) maximum stress at failure, (4) point of failure, (5) intervertebral disc stress, and (6) influence of adding a C2 pars screw to the multilevel construct. Results: The maximum moment at failure was higher in the LMS fixation group than in the TPS group. The maximum angulation in flexion allowed by LMS was higher than that by TPS. The maximum strain at failure was higher in the LMS group than in the TPS group. The maximum stress endured before failure was higher in the TPS group than in the LMS group. Intervertebral stress levels at C6–C7 and C7–T1 intervertebral discs were higher in the LMS group than in the TPS group. For both models where C2 fixation was performed, lower von Mises stress was recorded at the C2–C3 intervertebral disc level. Conclusions Ending a multilevel posterior cervical fixation construct with TPS fixation rather than LMS fixation at the C7 vertebra provides a stiff and more constrained construct system, with higher stress endurance to compressive force. The constraint and durability of the construct can be further enhanced by adding a C2 pars screw in the fixation system.